Home | Breeding

Category Archives: Breeding

Feed Subscription

Black Rough Neck Monitor Care and History

Although the Black Rough Neck Monitor, Varanus rudicollis, is rarely-seen in the wild, captive-bred individuals are often available.  This striking lizard utilizes a variety of very different habitats, so in a suitably large enclosure one can expect to see a many interesting behaviors.  This is definitely a species worth studying carefully, as we still have much to learn.  I’ve always wanted to feature them in large zoo exhibits, but was not able to drum up much interest, unfortunately.  Private keepers, however, have added greatly to what is known of this under-appreciated monitor.

Black Rough Neck Monitors remind me of Merten’s Water Monitors, Vanaus mersentsi, in general body form and especially in their ability to move about in trees, water and on land with equal ease (Note: the photo below is of a Merten’s Water Monitor; please click here for photos of Rough Neck Monitors)

 

Riverside rainforest habitat

Uploaded to Wikipedia Commons by Allie Caulfield

Range

The Black Rough Neck Monitor is found across a huge range that extends from southern Myanmar through Thailand and western Malaysia to Sumatra and Borneo, and also inhabits nearby offshore islands.  As it is difficult to observe, many believe that the range is greater than generally accepted.

 

Habitat

Although widely distributed, the Black Rough Neck has specific habitat requirements.  It seems restricted to rainforests near permanent water bodies and mangrove swamps.  Although believed to be highly arboreal, Black Rough Necked Monitors frequently forage on the ground and in the shallows of rivers and swamps.

 

Merten's Water Monitor

Uploaded to Wikipedia Commons by Jarek Tuszynski /

Description

The Black Rough Neck Monitor is stout in build and averages 3-4 feet in length, with some individuals reaching 5 feet.  The body color ranges from dark gray to nearly black; there is some evidence that different populations exhibit specific shades of gray or black.  The thick, pointed scales that encircle the neck are unique among monitors; I’ve not yet found a reputable published account of their function.  Extremely sharp claws (even by monitor standards!) assist it in climbing.

 

Enclosure

Like most monitors, Black Rough Necks are quite active, and will not thrive in close quarters.  Adults require custom-built cages measuring at least 6 x 4 x 6 feet; greater height is preferable.

 

Cypress mulch or eucalyptus bark may be used as a substrate.  Shy by nature, they are best provided with numerous caves, cork bark rolls and hollow logs in which to shelter, and stout climbing branches for climbing.  They prefer sheltering above ground (wild individuals often utilize tree hollows), so a cork bark roll or large nest box positioned among the branches would be ideal.

 

The cage should be located in a quiet, undisturbed area of the home, as Black Rough Neck Monitors are very aware of their surroundings and easily stressed.

 

Temperature

Black Rough Neck Monitors fare best when afforded a wide temperature gradient, such as 75-95 F; a dip to 70-73 F at night may be beneficial. The basking temperature should be kept at 120-140 F; some keepers go as high as 150F.  Incandescent bulbs http://www.thatpetplace.com/spot-day-white-bulbs may be used by day; ceramic heaters http://bitly.com/NSUMSq or red/black reptile “night bulbs” http://bitly.com/MS35s9 are useful after dark.

 

Provide your monitor with the largest home possible, so that a thermal gradient (areas of different temperatures) can be established.  Thermal gradients, critical to good health, allow reptiles to regulate their body temperature by moving between hot and cooler areas.  In small or poorly ventilated enclosures, the entire area soon takes on the basking site temperature.

 

Humidity

Humidity should average 60-85%, but dry areas must be available.  A commercial reptile mister will be helpful if your home is especially dry.  A water area large enough for soaking must be available.

 

Light

UVB exposure is essential.  If a florescent bulb is used (the Zoo Med 10.0 UVB Bulb is ideal), be sure that your pet can bask within 6-12 inches of it.  Mercury vapor and halogen bulbs broadcast UVB over greater distances, and provide beneficial UVA radiation as well.

 

tp35833

Diet

The few available studies and observations indicate that wild Black Rough Neck Monitors take a wide variety of prey animals, and that the diet may vary across the range.  Rodents, bats and other mammals, although consumed when available, do not comprise the bulk of the natural diet.  Wild individuals seem to feed primarily upon grasshoppers, roaches and other large insects, frogs, crabs, and snails.  Scorpions, termites, birds and their eggs, and fish have also been recorded as being consumed.

 

A rodent-only diet will not work well for Rough Necked Monitors. Youngsters should be fed largely upon roaches, super mealworms, snails, hornworms and other invertebrates, along with small whole fishes, un-shelled shrimp, fiddler and green crabs, crayfish and squid.  Mice should be provided once weekly, and hard-boiled eggs can be used on occasion.  All meals offered to growing monitors should be powdered with calcium, and a high-quality reptile vitamin/mineral supplement should be used 3x weekly.  I favor ReptoCal, ReptiVite and ReptiCal.

 

Rodents and whole fish can comprise 50% of the adult diet, with a variety of large insects, hard-boiled eggs, crayfish, squid, shrimp, snails and similar foods making up the balance.  Calcium and vitamin/mineral supplements should be used 1-2x weekly.  Large food items should be avoided; even where adult monitors are concerned, mice are preferable to small rats.

 

Temperament

Although not a species for beginners, Black Rough Neck Monitors adjust well to captivity when given proper care, and make fine, long-lived pets.  Initially shy, some learn to trust gentle caretakers, while others remain wary even after years in captivity.  A large, well-furnished cage will provide the security which is essential if they are to become approachable.

 

In common with all monitors, they are capable of inflicting serious injuries with their powerful jaws, long tails, and sharp claws.  Thick leather gloves should be worn when handling Black Rough Neck Monitors, as even tame individuals will cause deep scratches with their claws in the course of their normal movements.

 

Breeding:

A single male can be housed with 1 or 2 females, but they must be watched carefully.  The nesting area should be enclosed (i.e. a large tub or plastic storage container within a wooden box equipped with a single entrance hole) and stocked with 2-3 feet of a slightly moist mix of sand and top soil or peat moss.

 

Egg deposition generally occurs within 35-50 days of mating, but captive conditions can greatly affect the gestation period.  Clutches contain 4-15 eggs, which may be incubated in moist vermiculite at 85-90 F for 180-200 days.  Double and triple-clutching has been recorded. Hatchlings measure 8-11 inches in length and are attractively banded with yellow.

 

Please check out my posts on Twitter and Facebook.   Each day, I highlight breaking research, conservation news and interesting stories concerning just about every type of animal imaginable.  I look forward to hearing about your interests and experiences as well, and will use them in articles when possible.

 

Please also post your questions and comments below…I’ll be sure to respond quickly.  Thanks, until next time, Frank Indiviglio.

 

Further Reading

How to Breed Dwarf African Clawed Frogs

Hello, Frank Indiviglio here.  Dwarf African Clawed Frogs, also known as Dwarf African Frogs (Hymenochirus boettgeri and H. curtipes) are very popular pets, yet few hobbyists attempt to breed them in captivity. Reproduction sometimes occurs spontaneously, but unless one is prepared, the eggs and tadpoles rarely survive.  As both a lifelong frog enthusiast and career herpetologist, I find this to be a sad state of affairs.  For these tiny aquatic frogs can be easily induced to breed and exhibit some of the amphibian world’s most amazing reproductive behaviors – including a circular egg-laying “dance” that may go on for 7 hours!  The bizarre tadpoles are equipped with tubular mouths and swim in a head up position at the water’s surface, propelled by rapidly-beating tails.  Looking somewhat like tiny skin-divers, rearing a tankful of these charming little amphibians is a most interesting and pleasurable undertaking.

Amplexus

Uploaded to Wikipedia Commons by Quatermass

Distinguishing the Species and the Sexes

Hymenochirus boettgeri and H. curtipes are the only species regularly available in the pet trade.  Hymenochirus boettgeri has proportionally longer rear legs than H. curtipes, and its skin appears more granular.  The tadpoles are easy to distinguish (please see below).

Females are larger than males, and they are positively rotund when carrying eggs.  Males can be distinguished by their postaxillary glands, which appear as a tiny white bump behind each forearm. Read More »

The Best Reptile Egg Incubator – the Zoo Med Reptibator

Hello, Frank Indiviglio here.  Breeding reptiles is one of the most rewarding and enjoyable aspects of our hobby.  It is quite important as well, as zoos have neither the time nor space to care for all the species that are, or will soon be, in need of help.  Relatively common reptiles also deserve attention, as lessons learned about their reproductive biology are often applicable to rarer relatives.

t248523ZooMed’s reptile egg incubator, marketed as the Reptibator, utilizes heating technology that is a vast improvement over older (and very expensive!) incubators that I used while working at the Bronx and Staten Island Zoos.  In addition to allowing for finer temperature and humidity control, the Reptibator’s Pulse Proportional Thermostat conserves energy while cutting electric bills. Read More »

Turtle and Tortoise Eggs – Knowing When She is Ready to Lay

Hello, Frank Indiviglio here.  In the course of my work, I am often contacted by turtle owners whose pets cease feeding and become unusually restless.  The behavior appears suddenly, sometimes after many uneventful years – a Common Musk Turtle did so after 22 years in my collection – and seems to have no external cause.  A normally placid turtle may begin frantically paddling or wandering about, trying to climb the sides of the terrarium and escape.  Food, once the focus of the creature’s existence, is ignored.

Common Snappers hatching

Uploaded by Frank Indiviglio

It surprises some folks to learn that turtle and tortoise eggs may develop even if the female has never mated, and that mated animals may retain sperm and produce fertile eggs years later.  Unfortunately, gravid (egg-bearing) turtles can be very choosy when it comes to nesting sites…a ½ acre exhibit failed to satisfy some I’ve cared for at the Bronx Zoo!  If the eggs are not deposited, blockages due to over-calcification and life-threatening infections invariably result.  Fortunately, there are ways to “convince” your pet to lay her eggs; failing this, several effective veterinary options are available.

What To Do

If your female turtle or tortoise suddenly stops feeding and begins to act as described above, first check that something has not gone wrong in the environment.  Overheating, Lysol poured into the tank by a mischievous child (actual story), or cage-mate aggression can all cause similar behaviors.

If you suspect eggs, your best option would be to have radiographs done by a veterinarian (please post below if you need help in locating an experienced vet).  Your vet can determine how many eggs are present, approximately how far along they are in their development, and if problems related to unusual size or over-calcification can be expected.  Also, other health issues that may cause similar symptoms can be investigated. Read More »

How To Breed Green Anoles and Raise the Youngsters

Hello, Frank Indiviglio here.  With proper care, the Green or Carolina Anole, Anolis carolinensis, is quite willing to breed in captivity.  However, being relatively inexpensive, it is often considered a “beginner’s pet” and not worthy of serious attention.  This is a serious mistake, as anoles of all species are among the most interesting of all lizards.  In fact, the antics of a colony of Green Anoles that I exhibited at the Bronx Zoo regularly stole attention from the more “dramatic” but sedentary Water Moccasins that shared their quarters.  What’s more, we still have much to learn regarding Green Anole reproduction…hatchlings can be difficult to rear, and second-generation breeding is rare.  There’s plenty to challenge the well-experienced keeper, and information gathered will likely be applicable to rare and less-studied relatives. You can read about how to breed Green Anoles, Brown Anoles, Bark Anoles and many others below.  However, over 350 anole species have been described, and details vary.  Please post below for specific information on other anoles.

Anoles mating

Uploaded to Wikipedia Commons by Tom Adams

Getting Started

A proper habitat and well-nourished, healthy animals are essential for breeding success.  When conditions are not ideal, reptiles respond by eliminating non-essential activities such as breeding.  Green Anoles kept in bare, cramped terrariums and fed upon crickets and mealworms alone will not breed.  Please see this four-part article on Green Anole Care and Natural History for further information, and be sure to post any your questions below.

Natural Breeding Behavior

The Green Anole’s breeding season extends from April to September.  Males display with vigorous head-bobs and flared dewlaps. The dewlap reflects ultraviolet light and is perceived by the female as more brilliant than the red coloration that we see.

Males actively pursue females and, using their mouths, grasp them by the neck during copulation.  Please see the articles linked below for notes on distinguishing the sexes.  One or two eggs are deposited 2-4 weeks after mating occurs. Most females leave them on or just below the substrate, along a log or other structure, although some bury eggs in soil or secrete them below leaf litter.  Many individuals will deposit eggs above-ground if possible.  Hanging live plants surrounded by a substrate of sphagnum moss and coconut husk make ideal sites.  The “pool areas” incorporated into Hagen Smart Plants (intended as a deposition site for Poison Frog eggs) might be attractive to gravid anoles if filled with damp moss; I hope to try this out shortly.

Male display

Uploaded to Wikipedia Commons by R. Colin Blenis

Inducing Reproduction

Females seem able to retain sperm, but most mate several times each season.  Additional clutches are produced at varying intervals, to a total of 8-10 eggs per female.

Breeding may occur spontaneously, but will be more likely if your anoles are subjected to cyclic changes in temperature, light and humidity levels that mimic natural seasonal variations.  The Green Anole’s huge range extends from Oklahoma and South Carolina through Florida to Cuba and other Caribbean islands.  A 6-8 week “winter” featuring reductions in temperature, humidity, and day-length is very effective in bringing them into breeding condition.  Populations in the northern portions of the range experience longer and cooler winters than do those from the south.  Most pet trade animals, however, are collected in central/south Florida and Louisiana.

Anoles do not require true hibernation or brumation.  During the cooling off period, daytime temperatures can be kept at 81-83 F, with a warmer basking site available.  At night, temperatures should be allowed to dip to 62-68 F (60-65 F if your anoles originated in the northern portion of the range).  The daytime light cycle should gradually be reduced to 8 -10 hours.  Mist once daily, but be sure that the anoles are drinking regularly.  Lowering the humidity is not as critical as daylight and temperature reductions.

After 6-8 weeks, gradually increase day length, temperature, and humidity.  Providing a wide variety of novel food items is a time-honored way of inducing reproduction in a wide variety of species.  Try offering small roaches, silkworms, and wild-caught caterpillars, leaf hoppers, moths, beetles, earwigs and other invertebrates.  Reptile misters and foggers can be used to dramatically increase humidity levels as the breeding season arrives.  Please see these articles for further information on collecting insects.

Incubating the Eggs

Eggs may be incubated in vermiculite or moist sphagnum moss.  I prefer to use a vermiculite and water in a 1:1 ratio by weight (please see this article for details on setting this up), but success has been had by adding just enough water so that the substrate barely holds together when squeezed.

The incubation container (a plastic deli cup will do) is best kept in a small commercial reptile incubator at 82-88 F.  However, eggs may also be kept at room temperature in an appropriately-warm attic or similar location. Depending upon temperature and humidity, the eggs will hatch in 30-50 days.  Please post below for detailed information on incubation.

Juvenile

Uploaded to Wikipedia Commons by DragonTU84 DragonTU84 DragonTU84

Rearing the Young

Hatchling Green Anoles frustrate many hobbyists.  They are aggressive towards smaller cage-mates, prone to desiccation, and need ample exposure to UVB.  But in my experience, most failures are due to nutritional deficiencies. They will not thrive on pinheads and fruit flies alone.

Providing dietary variety can be difficult, given their size, but there are many options.  “Meadow plankton”, leaf litter invertebrates, tiny moths, termites, sap beetles, flour beetle grubs and other small invertebrates are essential.  Insect traps such as the Zoo Med Bug Napper will assist in the collection of tiny moths and other flying insects.  The information in this article on Feeding Poison Frogs is largely applicable.  Please also post your questions below.

Please check out my posts on Twitter and Facebook.   Each day, I highlight breaking research, conservation news and interesting stories concerning just about every type of animal imaginable.  I look forward to hearing about your interests and experiences as well, and will use them in articles when possible.

 Please also post your questions and comments below…I’ll be sure to respond quickly. 

Thanks, until next time,

Frank Indiviglio

 

Further Reading

Important Supplies for Green Anoles and Other Lizards

Green Anole Natural History

 

Scroll To Top